In WiMAX systems, a mobile station (MS) may be able to support multi-input, multi-output (MIMO) operations in which the MS can have multiple transmit and receive antennas.
To support a smooth handover between the WiMAX network and another RAT, such as CDMA and UMTS, an MS may be provisioned with circuitry allowing concurrent transmission and reception in multiple RATs. Unfortunately, this implies multiple sets of radio hardware at the MS, which increases cost and power consumption. In order to support multiple RATs with a single set of radio hardware, WiMAX supports a scanning mode, where the MS is allowed to leave the WiMAX network.
Unfortunately, scanning is disruptive to any active WiMAX service, as during conventional scanning, the MS cannot transmit and receive with the WiMAX network.